Yeah, I've seen a few of these as well, hanging on a plastic strip in the ROTS "super" section. I've seen the Vader one you're mentioning, as well as a couple other character specific pins...made in that animated Jedi Force-ish style that you can see on some of the coffee cups, etc. at SWShop.com. I haven't picked any up, but I was tempted to get a keychain. They had a mix of keychains and pins both at our local Wal-Mart.